N-Methyl-N,O-bis(trimethylsilyl)hydroxylamine: Preparation, Properties, and Utilization.

The title compound was readily prepared from MeNHOH·HCl under alkaline conditions with silylating reagents: use of either Me3SiSiMe3 as a ‘counterattack reagent’ or Me3SiCl in a classical procedure. Reaction of aldehydes or ketones with a stoicheiometric amount of the title compound gave the corresponding N-methyl nitrones in good to excellent yields. The reaction intermediates were hemiaminals, which decomposed to nitrones by a bimolecular push–pull mechanism. The title compound was used to protect a carbonyl group in a compound with another functionality, which was subsequently reduced in situ. Acidic work-up regenerated the carbonyl group. This new method of ‘protection–reduction–deprotection’ includes three transformations, which were carried out in one flask.